/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2007 Sun Microsystems, Inc.  Portions Copyrighted 2008 Richard Schilling.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
 *
 * Contributor(s): Richard Schilling (coderroadie@gmail.com)
 *
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package com.sun.mail.pop3;

import javax.mail.*;
import javax.mail.internet.*;
import javax.mail.event.*;
import java.io.InputStream;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.EOFException;
import java.util.Vector;
import java.util.StringTokenizer;
import java.lang.reflect.Constructor;

import com.sun.mail.util.LineInputStream;

/**
 * A POP3 Folder (can only be "INBOX").
 * See the <a href="package-summary.html">com.sun.mail.pop3</a> package
 * documentation for further information on the POP3 protocol provider.
 * <p>
 * 
 * @author Bill Shannon
 * @author John Mani (ported to the javax.mail APIs)
 */
public class POP3Folder extends Folder {

    private String name;
    private Protocol port;
    private int total;
    private int size;
    private boolean exists = false;
    private boolean opened = false;
    private Vector message_cache;
    private boolean doneUidl = false;

    POP3Folder(POP3Store store, String name) {
        super(store);
        this.name = name;
        if (name.equalsIgnoreCase("INBOX"))
            exists = true;
    }

    public String getName() {
        return name;
    }

    public String getFullName() {
        return name;
    }

    public Folder getParent() {
        return new DefaultFolder((POP3Store) store);
    }

    /**
     * Always true for the folder "INBOX", always false for
     * any other name.
     * 
     * @return true for INBOX, false otherwise
     */
    public boolean exists() {
        return exists;
    }

    /**
     * Always throws <code>MessagingException</code> because no POP3 folders
     * can contain subfolders.
     * 
     * @exception MessagingException always
     */
    public Folder[] list(String pattern) throws MessagingException {
        throw new MessagingException("not a directory");
    }

    /**
     * Always returns a NUL character because POP3 doesn't support a hierarchy.
     * 
     * @return NUL
     */
    public char getSeparator() {
        return '\0';
    }

    /**
     * Always returns Folder.HOLDS_MESSAGES.
     * 
     * @return Folder.HOLDS_MESSAGES
     */
    public int getType() {
        return HOLDS_MESSAGES;
    }

    /**
     * Always returns <code>false</code>; the POP3 protocol doesn't
     * support creating folders.
     * 
     * @return false
     */
    public boolean create(int type) throws MessagingException {
        return false;
    }

    /**
     * Always returns <code>false</code>; the POP3 protocol provides
     * no way to determine when a new message arrives.
     * 
     * @return false
     */
    public boolean hasNewMessages() throws MessagingException {
        return false;    // no way to know
    }

    /**
     * Always throws <code>MessagingException</code> because no POP3 folders
     * can contain subfolders.
     * 
     * @exception MessagingException always
     */
    public Folder getFolder(String name) throws MessagingException {
        throw new MessagingException("not a directory");
    }

    /**
     * Always throws <code>MethodNotSupportedException</code> because the POP3
     * protocol doesn't allow the INBOX to
     * be deleted.
     * 
     * @exception MethodNotSupportedException always
     */
    public boolean delete(boolean recurse) throws MessagingException {
        throw new MethodNotSupportedException("delete");
    }

    /**
     * Always throws <code>MethodNotSupportedException</code> because the POP3
     * protocol doesn't support multiple folders.
     * 
     * @exception MethodNotSupportedException always
     */
    public boolean renameTo(Folder f) throws MessagingException {
        throw new MethodNotSupportedException("renameTo");
    }

    /**
     * Throws <code>FolderNotFoundException</code> unless this
     * folder is named "INBOX".
     * 
     * @exception FolderNotFoundException if not INBOX
     * @exception AuthenticationException authentication failures
     * @exception MessagingException other open failures
     */
    public synchronized void open(int mode) throws MessagingException {
        checkClosed();
        if (!exists)
            throw new FolderNotFoundException(this, "folder is not INBOX");

        try {
            port = ((POP3Store) store).getPort(this);
            Status s = port.stat();
            total = s.total;
            size = s.size;
            this.mode = mode;
            opened = true;
        } catch (IOException ioex) {
            try {
                if (port != null)
                    port.quit();
            } catch (IOException ioex2) {
                // ignore
            } finally {
                port = null;
                ((POP3Store) store).closePort(this);
            }
            throw new MessagingException("Open failed", ioex);
        }

        // Create the message cache vector of appropriate size
        message_cache = new Vector(total);
        message_cache.setSize(total);
        doneUidl = false;

        notifyConnectionListeners(ConnectionEvent.OPENED);
    }

    public synchronized void close(boolean expunge) throws MessagingException {
        checkOpen();

        try {
            /*
             * Some POP3 servers will mark messages for deletion when
             * they're read. To prevent such messages from being
             * deleted before the client deletes them, you can set
             * the mail.pop3.rsetbeforequit property to true. This
             * causes us to issue a POP3 RSET command to clear all
             * the "marked for deletion" flags. We can then explicitly
             * delete messages as desired.
             */
            if (((POP3Store) store).rsetBeforeQuit)
                port.rset();
            if (expunge && mode == READ_WRITE) {
                // find all messages marked deleted and issue DELE commands
                POP3Message m;
                for (int i = 0; i < message_cache.size(); i++) {
                    if ((m = (POP3Message) message_cache.elementAt(i)) != null) {
                        if (m.isSet(Flags.Flag.DELETED))
                            try {
                                port.dele(i + 1);
                            } catch (IOException ioex) {
                                throw new MessagingException(
                                        "Exception deleting messages during close", ioex);
                            }
                    }
                }
            }

            port.quit();
        } catch (IOException ex) {
            // do nothing
        } finally {
            port = null;
            ((POP3Store) store).closePort(this);
            message_cache = null;
            opened = false;
            notifyConnectionListeners(ConnectionEvent.CLOSED);
        }
    }

    public boolean isOpen() {
        if (!opened)
            return false;
        if (store.isConnected())
            return true;
        try {
            close(false);
        } catch (MessagingException ex) {}
        return false;
    }

    /**
     * Always returns an empty <code>Flags</code> object because
     * the POP3 protocol doesn't support any permanent flags.
     * 
     * @return empty Flags object
     */
    public Flags getPermanentFlags() {
        return new Flags(); // empty flags object
    }

    /**
     * Will not change while the folder is open because the POP3
     * protocol doesn't support notification of new messages
     * arriving in open folders.
     */
    public synchronized int getMessageCount() throws MessagingException {
        if (!opened)
            return -1;
        checkReadable();
        return total;
    }

    public synchronized Message getMessage(int msgno) throws MessagingException {
        checkOpen();

        POP3Message m;

        // Assuming that msgno is <= total
        if ((m = (POP3Message) message_cache.elementAt(msgno - 1)) == null) {
            m = createMessage(this, msgno);
            message_cache.setElementAt(m, msgno - 1);
        }
        return m;
    }

    protected POP3Message createMessage(Folder f, int msgno) throws MessagingException {
        POP3Message m = null;
        Constructor cons = ((POP3Store) store).messageConstructor;
        if (cons != null) {
            try {
                Object[] o = { this, new Integer(msgno) };
                m = (POP3Message) cons.newInstance(o);
            } catch (Exception ex) {
                // ignore
            }
        }
        if (m == null)
            m = new POP3Message(this, msgno);
        return m;
    }

    /**
     * Always throws <code>MethodNotSupportedException</code> because the POP3
     * protocol doesn't support appending messages.
     * 
     * @exception MethodNotSupportedException always
     */
    public void appendMessages(Message[] msgs) throws MessagingException {
        throw new MethodNotSupportedException("Append not supported");
    }

    /**
     * Always throws <code>MethodNotSupportedException</code> because the POP3
     * protocol doesn't support expunging messages
     * without closing the folder; call the {@link #close close} method
     * with the <code>expunge</code> argument set to <code>true</code> instead.
     * 
     * @exception MethodNotSupportedException always
     */
    public Message[] expunge() throws MessagingException {
        throw new MethodNotSupportedException("Expunge not supported");
    }

    /**
     * Prefetch information about POP3 messages.
     * If the FetchProfile contains <code>UIDFolder.FetchProfileItem.UID</code>,
     * POP3 UIDs for all messages in the folder are fetched using the POP3
     * UIDL command.
     * If the FetchProfile contains <code>FetchProfile.Item.ENVELOPE</code>,
     * the headers and size of all messages are fetched using the POP3 TOP
     * and LIST commands.
     */
    public synchronized void fetch(Message[] msgs, FetchProfile fp) throws MessagingException {
        checkReadable();
        if (!doneUidl && fp.contains(UIDFolder.FetchProfileItem.UID)) {
            /*
             * Since the POP3 protocol only lets us fetch the UID
             * for a single message or for all messages, we go ahead
             * and fetch UIDs for all messages here, ignoring the msgs
             * parameter. We could be more intelligent and base this
             * decision on the number of messages fetched, or the
             * percentage of the total number of messages fetched.
             */
            String[] uids = new String[message_cache.size()];
            try {
                if (!port.uidl(uids))
                    return;
            } catch (EOFException eex) {
                close(false);
                throw new FolderClosedException(this, eex.toString());
            } catch (IOException ex) {
                throw new MessagingException("error getting UIDL", ex);
            }
            for (int i = 0; i < uids.length; i++) {
                if (uids[i] == null)
                    continue;
                POP3Message m = (POP3Message) getMessage(i + 1);
                m.uid = uids[i];
            }
            doneUidl = true;	// only do this once
        }
        if (fp.contains(FetchProfile.Item.ENVELOPE)) {
            for (int i = 0; i < msgs.length; i++) {
                try {
                    POP3Message msg = (POP3Message) msgs[i];
                    // fetch headers
                    msg.getHeader("");
                    // fetch message size
                    msg.getSize();
                } catch (MessageRemovedException mex) {
                    // should never happen, but ignore it if it does
                }
            }
        }
    }

    /**
     * Return the unique ID string for this message, or null if
     * not available. Uses the POP3 UIDL command.
     * 
     * @return unique ID string
     * @exception MessagingException
     */
    public synchronized String getUID(Message msg) throws MessagingException {
        checkOpen();
        POP3Message m = (POP3Message) msg;
        try {
            if (m.uid == POP3Message.UNKNOWN)
                m.uid = port.uidl(m.getMessageNumber());
            return m.uid;
        } catch (EOFException eex) {
            close(false);
            throw new FolderClosedException(this, eex.toString());
        } catch (IOException ex) {
            throw new MessagingException("error getting UIDL", ex);
        }
    }

    /**
     * Return the size of this folder, as was returned by the POP3 STAT
     * command when this folder was opened.
     * 
     * @return folder size
     * @exception IllegalStateException if the folder isn't open
     */
    public synchronized int getSize() throws MessagingException {
        checkOpen();
        return size;
    }

    /**
     * Return the sizes of all messages in this folder, as returned
     * by the POP3 LIST command. Each entry in the array corresponds
     * to a message; entry <i>i</i> corresponds to message number <i>i+1</i>.
     * 
     * @return array of message sizes
     * @exception IllegalStateException if the folder isn't open
     * @since JavaMail 1.3.3
     */
    public synchronized int[] getSizes() throws MessagingException {
        checkOpen();
        int sizes[] = new int[total];
        InputStream is = null;
        LineInputStream lis = null;
        try {
            is = port.list();
            lis = new LineInputStream(is);
            String line;
            while ((line = lis.readLine()) != null) {
                try {
                    StringTokenizer st = new StringTokenizer(line);
                    int msgnum = Integer.parseInt(st.nextToken());
                    int size = Integer.parseInt(st.nextToken());
                    if (msgnum > 0 && msgnum <= total)
                        sizes[msgnum - 1] = size;
                } catch (Exception e) {}
            }
        } catch (IOException ex) {
            // ignore it?
        } finally {
            try {
                if (lis != null)
                    lis.close();
            } catch (IOException cex) {}
            try {
                if (is != null)
                    is.close();
            } catch (IOException cex) {}
        }
        return sizes;
    }

    /**
     * Return the raw results of the POP3 LIST command with no arguments.
     * 
     * @return InputStream containing results
     * @exception IllegalStateException if the folder isn't open
     * @since JavaMail 1.3.3
     */
    public synchronized InputStream listCommand() throws MessagingException, IOException {
        checkOpen();
        return port.list();
    }

    /**
     * Close the folder when we're finalized.
     */
    protected void finalize() throws Throwable {
        super.finalize();
        close(false);
    }

    /* Ensure the folder is open */
    void checkOpen() throws IllegalStateException {
        if (!opened)
            throw new IllegalStateException("Folder is not Open");
    }

    /* Ensure the folder is not open */
    void checkClosed() throws IllegalStateException {
        if (opened)
            throw new IllegalStateException("Folder is Open");
    }

    /* Ensure the folder is open & readable */
    void checkReadable() throws IllegalStateException {
        if (!opened || (mode != READ_ONLY && mode != READ_WRITE))
            throw new IllegalStateException("Folder is not Readable");
    }

    /* Ensure the folder is open & writable */
    void checkWritable() throws IllegalStateException {
        if (!opened || mode != READ_WRITE)
            throw new IllegalStateException("Folder is not Writable");
    }

    /**
     * Centralize access to the Protocol object by POP3Message
     * objects so that they will fail appropriately when the folder
     * is closed.
     */
    Protocol getProtocol() throws MessagingException {
        checkOpen();
        return port;
    }

    /*
     * Only here to make accessible to POP3Message.
     */
    protected void notifyMessageChangedListeners(int type, Message m) {
        super.notifyMessageChangedListeners(type, m);
    }
}
